There's no hint of zoom on Apple's page of details of the new camera.
I suspect what you saw was the new cropping ability. Of course, you can crop with the iPhone 4, too. But that requires a free app from Adobe or another third-party app. Digital zoom would yield identical results. If you don't got optical zoom, you don't got zoom.
Also, given that with the 4s you get 8 mp, cropping is more feasible. I routinely crop images from a 6 mp camera (my Coolpix S10) with good results. I'm looking forward to that improvement.

I think the camera in my iPhone 4 is excellent for ordinary photos of landscapes or people, and it does a decent job on moderate closeups of, say, magazine or book pages (or secret military plans). It actually does a decent job in low light, but the results certainly don't look like a tastefully flash-lit image. The 4s camera should be much better.

"Design is not just what it looks like and feels like. Design is how it works."
Steve Jobs